package Chapter25.dao_.dao;

import Chapter25.dao_.utils.JDBCUtilsByDruid;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanHandler;
import org.apache.commons.dbutils.handlers.BeanListHandler;
import org.apache.commons.dbutils.handlers.ScalarHandler;

import java.sql.Connection;
import java.sql.SQLException;
import java.util.List;

/**
 * @author 杨森
 * @date 2022年11月23日 15:14
 * 开发BasicDAO，是其他DAO的父类
 */
public class BasicDao<T> {//泛型指定具体类型
    private QueryRunner qr = new QueryRunner();

    //开发通用的dml方法，针对任意的表
    public int update(String sql, Object... parameters) {
        Connection connection = null;
        try {
            connection = JDBCUtilsByDruid.getConnection();
            int update = qr.update(connection, sql, parameters);
            return update;
        } catch (SQLException e) {
            throw new RuntimeException(e);
        } finally {
            JDBCUtilsByDruid.close(null, null, connection);
        }
    }

    /*
     *
     * @param sql sql语句，可以有？
     * @param clazz 传入一个类得到class对象，比如Admin.calss
     * @param parameters 传入？的具体的值，可以是多个
     * @return java.util.List<T> 根据Admin.class返回对应的ArrayList集合
     */
    //返回多个对象（即查询的结果是多行的），针对任意表
    public List<T> queryMulti(String sql, Class<T> clazz, Object... parameters) {
        Connection connection = null;
        try {
            connection = JDBCUtilsByDruid.getConnection();
            return qr.query(connection, sql, new BeanListHandler<T>(clazz), parameters);

        } catch (SQLException e) {
            throw new RuntimeException(e);
        } finally {
            JDBCUtilsByDruid.close(null, null, connection);
        }
    }

    //查询单行结果的通用方法
    public T querySingle(String sql, Class<T> clazz, Object... parameters) {
        Connection connection = null;
        try {
            connection = JDBCUtilsByDruid.getConnection();
            return qr.query(connection, sql, new BeanHandler<T>(clazz), parameters);


        } catch (SQLException e) {
            throw new RuntimeException(e);
        } finally {
            JDBCUtilsByDruid.close(null, null, connection);
        }
    }

    //查询单行单列的方法，即返回单值的方法
    public Object queryScalar(String sql, Object... parameters) {
        Connection connection = null;
        try {
            connection = JDBCUtilsByDruid.getConnection();
            return qr.query(connection, sql, new ScalarHandler(), parameters);
        } catch (SQLException e) {
            throw new RuntimeException(e);
        } finally {
            JDBCUtilsByDruid.close(null, null, connection);
        }
    }

}
